lead poisoning

Lead Poisoning

Definition

Lead poisoning occurs when a person swallows, absorbs, or inhales lead in any form. The result can be damaging to the brain, nerves, and many other parts of the body. Acute lead poisoning, which is somewhat rare, occurs when a relatively large amount of lead is taken into the body over a short period of time. Chronic lead poisoning—a common problem in children—occurs when small amounts of lead are taken in over a longer period. The Centers for Disease Control and Prevention (CDC) defines childhood lead poisoning as a whole-blood lead concentration equal to or greater than 10 micrograms/dL.

Description

Lead can damage almost every system in the human body, and it can also cause high blood pressure (hypertension). It is particularly harmful to the developing brain of fetuses and young children. The higher the level of lead in a child's blood, and the longer this elevated level lasts, the greater the chance of ill effects. Over the long term, lead poisoning in a child can lead to learning disabilities, behavioral problems, and even mental retardation. At very high levels, lead poisoning can cause seizures, coma, and even death. According to the National Center for Environmental Health, there were about 200 deaths from lead poisoning in the United States between 1979 and 1998. Most of the deaths were among males (74%), African Americans (67%), adults over the age of 45 (76%), and Southerners (70%).

About one out of every six children in the United States has a high level of lead in the blood, according to the Agency for Toxic Substances and Disease Registry. Many of these children are exposed to lead through peeling paint in older homes. Others are exposed through dust or soil that has been contaminated by old paint or past emissions of leaded gasoline. Since children between the ages of 12-36 months are apt to put things in their mouths, they are more likely than older children to take in lead. Pregnant women who come into contact with lead can pass it along to the fetus.

Over 80% of American homes built before 1978 have lead-based paint in them, according to the Centers for Disease Control and Prevention (CDC). The older the home, the more likely it is to contain lead paint, and the higher the concentration of lead in the paint is apt to be. Some homes also have lead in the water pipes or plumbing. People may have lead in the paint, dust, or soil around their homes or in their drinking water without knowing it, since lead can't be seen, smelled, or tasted. Because lead doesn't break down naturally, it can continue to cause problems until it is removed.

Causes and symptoms

Before scientists knew how harmful it could be, lead was widely used in paint, gasoline, water pipes, and many other products. Today house paint is almost lead-free, gasoline is unleaded, and household plumbing is no longer made with lead materials. Still, remnants of the old hazards remain. Following are some sources of lead exposure:

Lead-based paint. This is the most common source of exposure to large amounts of lead among preschoolers. Children may eat paint chips from older homes that have fallen into disrepair. They may also chew on painted surfaces such as windowsills. In addition, paint may be disturbed during remodeling.

Dust and soil. These can be contaminated with lead from old paint or past emissions of leaded gasoline. In addition, pollution from operating or abandoned industrial sites and smelters can find its way into the soil, resulting in soil contamination.

Drinking water. Exposure may come from lead water pipes, found in many homes built before 1930. Even newer copper pipes may have lead solder. Also, some new homes have brass faucets and fittings that can leach lead.

Jobs and hobbies. A number of activities can expose participants to lead. These include making pottery or stained glass, refinishing furniture, doing home repairs, and using indoor firing ranges. When adults take part in such activities, they may inadvertently expose children to lead residue that is on their clothing or on scrap materials.

Food. Imported food cans often have lead solder. Lead may also be found in leaded crystal glassware and some imported ceramic or old ceramic dishes (e.g., ceramic dishes from Mexico). A 2003 study of cases of lead poisoning in pregnant women found that 70% of the patients were Hispanics, most of whom had absorbed the lead from their pottery. In addition, food may be contaminated by lead in the water or soil.

Moonshine whiskey. Lead poisoning from drinking illegally distilled liquor is still a cause of death among adults in the southern United States.

Gunshot wounds. Toxic amounts of lead can be absorbed from bullets or bullet fragments that remain in the body after emergency surgery.

Chronic lead poisoning

New evidence suggests that lead may be harmful to children even at low levels that were once thought to be safe, and the risk of damage rises as blood levels of lead increase. The symptoms of chronic lead poisoning take time to develop, however. Children can appear healthy despite having high levels of lead in their blood. Over time, though, problems such as the following may arise:

learning disabilities

hyperactivity

mental retardation

slowed growth

hearing loss

headaches

It is also known that certain genetic factors increase the harmful effects of lead poisoning in susceptible children; however, these factors are not completely understood as of 2003.

Lead poisoning is also harmful to adults, in whom it can cause high blood pressure, digestive problems, nerve disorders, memory loss, and muscle and joint pain. In addition, it can lead to difficulties during pregnancy, as well as cause reproductive problems in both men and women.

More recently, chronic exposure to lead in the environment has been found to speed up the progression of kidney disorders in patients without diabetes.

Acute lead poisoning

Acute lead poisoning, while less common, shows up more quickly and can be fatal. Symptoms such as the following may occur:

severe abdominal pain

diarrhea

nausea and vomiting

weakness of the limbs

seizures

coma

Diagnosis

A high level of lead in the blood can be detected with a simple blood test. In fact, testing is the only way to know for sure if children without symptoms have been exposed to lead, since they can appear healthy even as long-term damage occurs. The CDC recommends testing all children at 12 months of age and, if possible, again at 24 months. Testing should start at six months for children at risk for lead poisoning. Based on these test results and a child's risk factors, the doctor will then decide whether further testing is needed and how often. In some states, more frequent testing is required by law.

Children at risk

Children with an increased risk of lead poisoning include those who:

Live in or regularly visit a house built before 1978 in which chipped or peeling paint is present.

Live in or regularly visit a house that was built before 1978 where remodeling is planned or underway.

Continuous exposure to lead can damage nearly every system in the human body and is particularly harmful to the developing brain of fetuses and young children. Common sources of lead exposure include lead-based paint, dust and soil, drinking water, food from cans, and eating utensils, such as plates and drinking glasses, that are lead-based.

(Illustration by Electronic Illustrators Group.)

Have a brother or sister, housemate, or playmate who has been diagnosed with lead poisoning.

Have the habit of eating dirt, or have been diagnosed with pica.

Live with an adult whose job or hobby involves exposure to lead.

Live near an active lead smelter, battery-recycling plant, or other industry that can create lead pollution.

Adults at risk

Testing is also important for adults whose job or hobby puts them at risk for lead poisoning. This includes people who take part in the following activities:

glazed pottery or stained glass making

furniture refinishing

home renovation

target shooting at indoor firing ranges

battery reclamation

precious metal refining

radiator repair

art restoration

Treatment

The first step in treating lead poisoning is to avoid further contact with lead. For adults, this usually means making changes at work or in hobbies. For children, it means finding and removing sources of lead in the home. In most states, the public health department can help assess the home and identify lead sources.

If the problem is lead paint, a professional with special training should remove it. Removal of lead paint is not a do-it-yourself project. Scraping or sanding lead paint creates large amounts of dust that can poison people in the home. This dust can stay around long after the work is completed. In addition, heating lead paint can release lead into the air. For these reasons, lead paint should only be removed by someone who knows how to do the job safely and has the equipment to clean up thoroughly. Occupants, especially children and pregnant women, should leave the home until the cleanup is finished.

Medical professionals should take all necessary steps to remove bullets or bullet fragments from patients with gunshot injuries.

Chelation therapy

If blood levels of lead are high enough, the doctor may also prescribe chelation therapy. This refers to treatment with chemicals that bind to the lead and help the body pass it in urine at a faster rate. There are four chemical agents that may be used for this purpose, either alone or in combination. Edetate calcium disodium (EDTA calcium) and dimercaprol (BAL) are given through an intravenous line or in shots, while succimer (Chemet) and penicillamine (Cuprimine, Depen) are taken by mouth. (Although many doctors prescribe penicillamine for lead poisoning, this use of the drug has not been approved by the Food and Drug Administration.)

Alternative treatment

Changes in diet are no substitute for medical treatment. However, getting enough calcium, zinc, and protein may help reduce the amount of lead the body absorbs. Iron is also important, since people who are deficient in this nutrient absorb more lead. Garlic and thiamine, a B-complex vitamin, have been used to treat lead poisoning in animals. However, their usefulness in humans for this purpose has not been proved. Nutritional, botanical, and homeopathic medicines can be administered once the source is removed, to help correct any imbalances brought on by lead toxicity.

Prognosis

If acute lead poisoning reaches the stage of seizures and coma, there is a high risk of death. Even if the person survives, there is a good chance of permanent brain damage. The long-term effects of lower levels of lead can also be permanent and severe. However, if chronic lead poisoning is caught early, these negative effects can be limited by reducing future exposure to lead and getting proper medical treatment.

Key terms

Chelation therapy — Treatment with chemicals that bind to a poisonous metal and help the body pass it in urine at a faster rate.

Penicillamine (Cuprimine, Depen) — A drug used to treat medical problems (such as excess copper in the body and rheumatoid arthritis) and to prevent kidney stones. It is also sometimes prescribed to remove excess lead from the body.

Pica — An abnormal appetite or craving for nonfood items, often such substances as chalk, clay, dirt, laundry starch, or charcoal.

Prevention

Keep the areas where children play as clean and dust-free as possible.

Wash pacifiers and bottles when they fall to the floor, and wash stuffed animals and toys often.

Make sure children wash their hands before meals and at bedtime.

Mop floors and wipe windowsills and other chewable surfaces, such as cribs, twice a week with a solution of powdered dishwasher detergent in warm water.

Plant bushes next to an older home with painted exterior walls to keep children at a distance.

Plant grass or another ground cover in soil that is likely to be contaminated, such as soil around a home built before 1960 or located near a major highway.

Have household tap water tested to find out if it contains lead.

Use only water from the cold-water tap for drinking, cooking, and making baby formula, since hot water is likely to contain higher levels of lead.

If the cold water hasn't been used for six hours or more, run it for several seconds, until it becomes as cold as it will get, before using it for drinking or cooking. The more time water has been sitting in the pipes, the more lead it may contain.

If you work with lead in your job or hobby, change your clothes before you go home.

lead poi·son·ing

acute or chronic intoxication by lead or any of its salts; symptoms of acute lead poisoning usually are those of acute gastroenteritis in adults or encephalopathy in children; chronic lead poisoning is manifested chiefly by anemia, constipation, colicky abdominal pain, neuropathy with paralysis with wrist-drop involving the extensor muscles of the forearm, bluish lead line of the gums, and interstitial nephritis; saturnine gout, convulsions, and coma may occur.

lead poisoning

(lĕd)

n.

Acute or chronic poisoning by lead or any of its salts, with the acute form causing severe gastroenteritis and encephalopathy and the chronic form causing anemia and damage to the gastrointestinal tract and nervous system. Also called saturnism.

lead poisoning

[led]

a toxic condition caused by the ingestion or inhalation of lead or lead compounds. Many children develop the condition as a result of eating flaked lead paint. Poisoning also occurs from the ingestion of water from lead pipes and lead salts in certain foods and wines, the use of pewter or earthenware glazed with a lead glaze, and the use of leaded gasoline. Inhalation of lead fumes is common in industry. The acute form of intoxication is characterized by a burning sensation in the mouth and esophagus, colic, constipation or diarrhea, mental disturbances, and paralysis of the extremities, followed in severe cases by convulsions and muscular collapse. Chronic lead poisoning, which is characterized by extreme irritability, anorexia, and anemia, may progress to the acute form. Encephalopathy must be anticipated in children with lead poisoning.

observations Lead poisoning is frequently asymptomatic, with mild toxicity. Likely initial manifestations include loss of appetite, abdominal discomfort, constipation, fatigue, irritability, headache, insomnia, and myalgia. Toxicity leads to three major clinical syndromes: cerebral (hyperactivity, behavior problems, learning problems, neurological disability, and/or mental retardation); neuromuscular (peripheral neuritis, paresthesias, and poor coordination); and alimentary (anorexia, abdominal cramping, weight loss, intestinal spasm, and rigidity of abdominal wall). Lead exposure in pregnant women can retard fetal development. Diagnosis is made by measuring lead levels in the blood, which will be greater than 10 μg/dl. Blood studies will also reveal a mild anemia with basophilic stippling. Chronic exposure may lead to renal failure, liver damage, and encephalopathy with blindness, seizures, paralysis, coma, and death.

interventions Treatment is dictated by serum lead levels. Children with levels between 10 and 19 μg/dl are treated conservatively with calcium, iron, zinc, and vitamin C supplements. They are placed on an elevated-protein-reduced fat diet to reduce lead absorption. For children with blood levels between 20 and 44 μg/dl, case management with environmental assessment is recommended, with aggressive control and removal of lead hazards. Case reports are made to the local health department for lead levels more than 20 μg/dl. All occupationally related cases should be reported to OSHA. Chelation with succimer and edetate calcium disodium (EDTA) is used in cases with blood levels greater than 45 μg/dl or in refractory cases.

nursing considerations All health care providers play an important role in the prevention of and screening for lead poisoning. All children should be screened for lead levels starting at 6 months to 1 year of age. Families should be educated about the risks of exposure to lead and instructed in the detection, removal, or treatment of potential sources of lead in and around the home. When the child has elevated lead levels, the focus is on aggressive reduction of further lead exposure. Education in diet and supplement therapy and the importance of continuing monitoring of blood levels is also necessary. Families of children undergoing chelation need instructional preparation for the procedure. EMLA cream should be applied before chelation injections, and EDTA should be mixed with succimer to reduce pain associated with the injections. Seizure precautions should be instituted for children with high lead blood levels. Renal function should be assessed through urinalysis, and lead blood levels rechecked after chelation. If lead exposure is occupationally related, workers should be instructed in the importance and consistent use of proper safety equipment such as respirators.

Lead poisoning

lead poi·son·ing

(led poy'zŏn-ing)

Acute or chronic intoxication by lead or any of its salts; symptoms of acute lead poisoning usually are those of acute gastroenteritis in adults or encephalopathy in children; chronic lead poisoning is manifested chiefly by anemia, constipation, colicky abdominal pain, neuropathy with paralysis (especially wrist-drop involving the extensor muscles of the forearm) bluish lead line of the gums, and interstitial nephritis; saturnine gout, convulsions, and coma may occur. Synonym(s): plumbism.

lead poisoning

The toxic effect of lead and lead compounds. Acute poisoning, from a large dose, causes abdominal pain, vomiting, diarrhoea, muscle weakness, convulsions, coma and death. Small amounts of lead taken in over long periods accumulate in the body and cause damage to brain function with headache, loss of physical coordination, loss of intellectual ability and memory, and abnormal behaviour.

Devonshire,

city in England.

Devonshire colic - colic which was first discovered in the city of Devonshire; caused by drinking cider made in lead-lined presses. Synonym(s): lead poisoning

lead poi·son·ing

(led poy'zŏn-ing)

Acute or chronic intoxication by lead or any of its salts; symptoms of acute lead poisoning usually are those of acute gastroenteritis in adults or encephalopathy in children; chronic lead poisoning is manifested chiefly by anemia, constipation, colicky abdominal pain, finding of a bluish lead line of the gums, and interstitial nephritis; gout, convulsions, and coma may occur.

Patients with long-standing leadinduced nephropathy have shown slight improvements in renal function in response to prolonged EDTA chelation therapy (26,48), but it is unknown whether chelation therapy would also benefit patients suffering from other manifestations of chronic lead exposure.

We report here on the use of CPT to examine different nerve fiber populations in the upper extremities of a group of current lead workers with substantial chronic lead exposure and a broad range of ergonomic stressors (ESs).

Other studies have found measures of chronic lead exposure associated with changes in nerve conduction velocity at a time when PbB was not (Chia et al.

In the context of the neurobehavioral deficits exhibited by the twins, it is possible that these outcomes are to some extent the result of adverse cerebrovascular events brought about as the result of chronic lead exposure.

If so, this suggests that chronic lead exposure caused a loss of neurons in the hippocampus, frontal cortex, and midbrain.

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